The present invention relates to a plastic optical transmission body, especially to a heat-resisting plastic optical fiber and a method of manufacturing the same.
The conventional plastic optical fiber is manufactured by hot-molding transparent thermoplastic polymer using a melting state as proposed in document 1.
Typical core material for this plastic optical fiber is polymethyl methacrylate or polystyrene, and such a plastic optical fiber is recently being put to practical use in many fields. As for the plastic optical fiber, making to high heat resistance will be hoped for the future. However, the upper bound temperature for which the above-mentioned optical fiber can be used is low with about 85° C. from the restriction on heat resistance of the resin which consists of polymethyl methacrylate or polystyrene.
On the other hand, a method of providing the heat resistance to a plastic optical fiber includes a method of using transparent heat-resisting thermoplastic resin such as polycarbonate or norbornene system polymers as described in document 5, and a manufacturing method in which after the preform of heat-resisting plastic is drawn using a melting state to form core material, and clad material is spread on outer thereof, radiation is applied to the plastic optical fiber obtained by drying the core material as described in document 2.
Moreover, there is a method of obtaining the plastic optical fiber with heat resistance as described in document 3, in which after making the clad tube, composition which is precursor of core material is injected into a clad tube and hardened.
[Document 1] Japanese Patent Publication No. 58-16163
[Document 2] Japanese Patent Publication No. 6-14127
[Document 3] Japanese Patent Application Laid-Open No. 57-102604
[Document 4] Japanese Patent Application Laid-Open No. 2004-212712
[Document 5] Kyoritsu Shuppan, Plastic Optical Fiber edited by POF consortium, pp 79-120 (1997)